I think that you have missed the point. Women's sizes are not supposed to make sense. They are supposed to make women think that they are thinner than they really are.
Women's sizes that make sense.
When I was a young'un, missy sizes started at size 10, and juniors at size 9. Over the years the size designations got smaller, but the women didn't.
Men's sizes make sense. You measure the various pieces that the clothes are up against, and just pick your clothing accordingly.
Waist, inseam, chest, arm, neck. That's all I need to know.
For women, you know just the size. Size 10, for example. WTF does size 10 mean?!?!?!?